Turbine



May 18, 1937.

A. LYSHOLM TURBINE Filed Feb. 9, 1954 3 Sheets-Sheet 1 l VENTOR d5; ATTNEY May 18, 1937. A. LYSHQLM 2,080,425

TURBINE Filed Feb. 9, 1954 5 Sheets-Sheet 2 A; A 'oRNEY A. LYSHOLM May18, 1937.

TURBINE Filed Feb. 9, 1934 3 Sheets-Sheet 3 Q i, 3, Y g

ATTORNEY I 50 Figs. '7 and 8 are enlarged sectional views showthisdiameter may be, for example, 200 The Patented May 18, 1937 I UNITEDSTATES PATENT OFFICE TURBINE Ali Lysholm, Stockholm, Sweden, asslgnor toAktiebolaget Milo, Stockholm, Sweden, a corporation oi SwedenApplication February 9, 1934, Serial No. 710,465 In Germany February 10,1933 2': Claims. (01. 253-69) Briefly stated, a general object of theinvention nated generally at A and an axial flow turbine is theprovision of improved gas turbine strucdesignated generally at B. i Theturbine rotor, ture whereby gaseous motive fluid having the indicatedgenerally at l0, and the compressor above mentioned temperature andpressure charrotor, designated generally at H, are mounted 5 acteristicsmay be utilized practically in an axial on a common shaft designatedgenerally at ll. 5 flow turbine of the multiple stage kind giving ShaftI l, in the illustrated embodiment, is built high thermodynamicefliciency. This general obup of a plurality of hollow sections l8, l8and ject is principally attained by the provision of a 20, and issupported at its ends in the journal novel form of turbine structureembodying a bearings 22 and 24. An intermediate shaft bearmultiplicityof stages of axial flowreaction blading 26 is also provided. 10 ing inwhich the path of flow for motive fluid The compressor A draws in airthrough a D through the blade system is of progressively inrality ofinlet openings, one of which is shown at creasing mean diameter from aninlet end of 2 and discharges the compressed air throu h relativelysmall diameter with full admission or he annul r discharge passage 30.The com- 5 motive fluid t t blade system and in hich pressed air flowsin the direction of the arrow 32 the lengths of the turbine blades aremuch greatp st the outside of a combustion chamber 34 and er withreference to the mean diameters of the enters the chamber from the rearthrough a respective blade rows, particularly at the inlet plurality ofinl peni gs 36 distributed around and of t m system th is th case withthe perimeter of the rear end of the chamber. 5 0 the practice of theprior art. In accordance Air also flows through a plurality 0 air inletwith the invention, the lengths of the turbine cones 38, eachdischarging t u h an opening blades at the inlet end of the turbine areat and in the current o air Passing through least ten per cent 01' themean diameters of the each se 1 95, w ic may be considered respectiveblade rows and are preferably of the as primary ail, fuel. example, udeOil. is

5 order of one-fifth of such diameters. The term injected by means ofnozzles ition 01' the 5 "mean diameter as herein employed designatesfuel is effected in known manner, a d t ough the diameter of a blade rowmeasured from center Suitable regulating pp which so ay be to center ofdiametrically opposed blades in the known form and which need not bedescribed blade herein, the quantity of fuel passed to the nozzles The.detailed nature of the above general ob- 40 through t uel s ly pipes I2.is suitably ject and of further and more detailed objects of a ed sothat the air is heated to th te the invention. together with the mannerin which D e desired for the motive fluid for the turthe several objectsare attained, will appear more bineve fl d is discharged from thecomclearly in the ensuing description of the several bustion chamber 34through the annular dis- 35 forms of apparatus illustrated in theaccompanycharge passage 44, which is advantageously proing drawings, inwhich: vided with stationary guide vanes for guiding- Fig. 1 is alongitudinal sectional view of a turth m ti fluid i t th first; r ofmoving bine comp s r un m dyi e inv n io turbine blades. The motivefluid, before it enters Fig. 2 is a SECtiOIl taken on the line 0f theturbine proper is not passed through now 1; which serve to increase thevelocity and reduce Fig. 3 is a section on enlarged scale of part of thetemperature and because of the resulting the blade System P 1; hightemperature or the motive fluid entering Fig. 4 isa longitudinalsectional view of anthe first row of moving turbine blades this row 2:;g g figg gg g zfi ggg of and the adjacent rows at the inlet end of the45 Fig. 4 turbine are subjected to very high temperatures, Fig- 6 is afragmentary Section showing a and accordingly the diameter of the firstrow of different form of turbine shaft heating arrangebladesand theadjacent rows is kept as man ment; and as possible. In a turbine oi. thekind illustrated.

ing diiferent turbine blade structures in accordlength it of the t i as, whic in the ance t t invention, illustrated embodiment, in accordancewith the Turning now to Fig. 1, the turbine compressor resent vent on,is lo in mp s w t unit illustrated compris s a compressor desigthe meandiameter or the blade row, and, as

.front end bearing 22.

shown, is approximately 20 per cent of the mean diameter, or about 40mm.

The turbine of the kind illustrated in Fig. 1 may be employed either toextract all the useful energy possible from the motive fluid and convertit into mechanical energy, in which case power over and above thatrequired to operate the compressor will be obtained, which power-may beconveniently taken off from a shaft attached to the forward end 46 ofthe shaft I4, or less than the total available energy of the motivefluid may be converted into mechanical energy in the turbine and theresulting exhaust gases of high velocity as discharged from the turbinemay be employed to produce propulsion by reactive or rocket effect. Inthe embodiment illustrated, the latter form of turbine is shown, theblade length :r at the exhaust end of the turbine being little, if any,longer than the blade length ax, at the inlet end of the turbine. As aconsequence, the ratio of the blade lengths to the mean diameters of therows of blades decreases from the inlet to the outlet end of the turbinerather than remaining substantially constant, as is the case where it isdesired to convert the maximum available energy in the motive fluid tomechanical work. In the illustrated embodiment, the combustion chamber34 is in the form'of a hollow annular shell which surrounds the turbinecasing. At the end of the combustion chamber adjacent to the compressora number of angularly disposed conduits 48 are provided, which permitair flowing in the direction of the arrow 50 to the space 52 to pass tothe space 54 between the turbine casing and the inner wall of thecombustion chamber 34. A part of the air which flows to space 52 passesalong the path indicated by the arrow 56 and enters the turbine bladingin the form of a thin annular stream between the stream of hot gas fromthe main outlet 34 and the turbine shaft. This thin stream of relativelycool air serves to protect the intermediate shaft bearing 26 and packing58 from heat radiated from the combustion chamber. The compressorcasingis preferably built up of a number of similar sections 60 suitablybolted or welded together, the forward end of the casing being providedby an end section 62 and the rearward end of the casing being providedby an end section 65. Section 62 provides the air inlet openings 28 andalso serves to support the A conical plate 56 secured to section 64,preferably by welding, serves to support the intermediate shaft bearing26. Plate 66 carries a circular flange 68 which serves to support theforward end of the turbine casing in a manner to be described. Theturbine casing 10 terminates at its forward end in a conical portionseen at 12 terminating in an annular flange l4. Flange I4 is connectedto the flange 68 by means of a plurality of radially extending pins orbolts 16 which permit relative movement between the two flanges inradial direction to compensate for expansion and contraction of theparts at different rates. The conical part 12 of the turbine casing isprovided with a number of openings through which the main part of thecombustion chamber 34 is connected with the outlet part 35 which formsin effect an admission chamber for the turbine. The spaces between theseopenings provide for the conduits 48 through which air flows to thespaces 54.

In accordance with one phase of the present invention the entire turbinecasing is made up as a single piece, and, as will be observed from Fig.1, the diameter of the casing increases from the inlet end to the outletend of the turbine, in order to accommodate the increased diameters ofthe rows of turbine blades, in a series of steps. The wall thickness issubstantially uniform from end to end of the casing and, as will benoted from the figure, both the inner and outer surfaces of the casingare stepped in substantially the same manner. The wall of the casing iscomparatively thin. This thin wall section is made possible because thecasing is in one piece, and the thin casing of the form shown is ofsubstantial advantage in the construction of a turbine designed tooperate with motive fluid at the temperatures contemplated because ofthe fact that the casing is comparatively rapidly and uniformly heatedby the motive fluid, so that expansion of the casing is not onlycomparatively uniform but it also is heated and expands more nearlytogether with the turbine shaft than would otherwise be the case.

The turbine rotor consists of the hollow shaft part 20 which in thepresent embodiment has integral therewith the discs 18 carrying the rowsof moving turbine blades (see also Fig. 3). The blades 80 may be securedto the discs 18 by one of a number of difierent forms of mechanicalconnection such, for example, as dove-tail and bolt connections, butsuch connections, regardless of their specific forms, are furthersecured by welding. In the arrangement shown in Fig. 3 the-welds areindicated at 82. The welding of these parts is very important in theturbine construction, since the operating temperatures for which theturbine is designed are such as to produce "creep of the metal, andwelding of the parts is highly desirable to prevent loosening of theconnections due tocreep of the metal. At their outer ends the blades 80are suitably connected to an annular ring 8 5.

The guide blade structure comprises a plurality of annular guide bladerings 86, which are 2 shaped in cross section, to which the outer endsof the stationary guide blades 88 are secured. The inner ends of theguide blades are secured by connections including welds such as areshown at 90 to an inner guide blade disc 92. The welding of the Jointsin the guide blade structure is equally as important as in the movingblade structure in order to prevent loosening of the connections due tocreep of the metal.

Rings 86 are attached to the turbine casing 10 by means of a pluralityof radially extending bolts or pins 94. The outer rings 84 of the moving blade rows are provided with a plurality of packing edges. In theembodiment illustrated, the ring 84 is provided with axially extendingedges 96 and 98 adapted to cooperate with radial faces of the rings 86at each side of the moving blade row, and radially extending edges I00and I02, the former cooperating with a cylindrical surface of anadjacent stationary ring 86 and the latter cooperating with an innercylindrical surface of the casing 10. The stationary guide discs 92 arepacked with respect to the rotor in' substantially the same way. Theinner part of each disc is provided with axially extending packing edgesI04 and 16 adapted to cooperate with suitable radially extendingsurfaces on the rotor, and the rotor is provided with two radiallyextending packing edges I08 and I I0, preferably of different diameter,cooperating with suitable cylindrical surfaces on the disc 92.

Referring again to Fig. 1, an outer shell H2 is secured to thecompressor casing part 64, and to the rearward end of this shell issecured a'flange II4 which may be advantageously welded as at I I8. Ahannular plate I I8 is secured to the flange H4 in any suitable manner,and the exhaust end I of the turbine casing I0 is secured to this plate-Extending radially inwardly from the part I20 of the turbine casing is aplurality of ribs I22 which ,are'preferably stream-lined in crosssection and the'inner ends of these ribs are joined by a ring part I24.A conical plate I28 is secured to ring I24 and serves to carry theturbine shaft bearing 24. The bearing 24 and the turbine partsassociated therewith are protected against hot exhaust gases by means ofa shield I28 01 generally conical form, which extends from the outlet ofthe turbine blade system to a rounded point indicated at I30 at therearward end of the apparatus. The shape of the shield I28 is ofimportance in securing flow of exhaust gas from the turbine with minimumoutlet loss, and this shape of the shield is particularly important incases where the reactive effect ofthe exhaust gases is to be utilizedfor rocket propulsion.

In accordance with theinvention the plate I I8 is made relatively thinand flexible in order to compensate for relative axial expansion betweenthe turbine casing I0 and the outer shell I I2. The arrangement wherebythe rear shaft bearing 24 is carried by the exhaust end of the casingand the arrangement of the bearing within the annular exhaust passageinsures minimum relative axial movement between the bearing and theshaft under the influence of expansion and contraction,

. and the nature of the bearing permits the shaft to expand freely whenheated.

Turning now more particularly to Figs. 4 to 8. a somewhat differentconstruction is illustrated. In this embodiment the turbine is designedto convert as much as possible of the energy of the motive fluid intomechanical work, and accordingly the relation between the length of theblades in a given blade row and the mean diameter of the given blade row.is substantially the same from the inlet to the outlet end of theturbine. As will be evident from Fig. 4 the absolute len th :n' of theblades in the last row is substantially greater than the absolute lengtha: of the blades in the first row.

The. turbine casing I 32 is, like the casing illustrated in Fig. 1, madein one piece and in a series of steps corresponding to the number ofturbine stages. Adjacent to the inlet end of the turbine the casing I32is connected to a conical flange I34 having a radially extending flangeI38 adapted to be secured to a casing part I30 for an associatedmachine, which latter part may advantageously provide a support for acenter shaft bearing I40. The parts I32 and I34 are connected by meansof a plurality of radially extending bolts or pins I42, and these pinsare preferably held against radial displacement by means 'of plugs I44threaded into countersunk recesses I48 in the part I34. The turbinecasing I32 is preferably surrounded by a shell I48 of appropriate form.

' A ring flanged at I50 is secured to the flange I52 at the exhaust endof the turbine casing. and th s ring is connected to a conical end wallI54 by means of a plurality of radially extending webs I58, preferablyof stream-linesection as shown in Fig. 5. Webs I22, shown in Fig. l, areadvantageously of the same cross sectional contour as the webs I58. Theend wall I54 carries the shaft bearing for supporting the exhaust end ofthe turbine shaft, and in the illustrated embodiment this bearingcomprises a bearing block I58 suitthe spaces I14 in known manner.

between the conical part I34 and part I38 there I60 and I88 serves tohold the turbine shaft against axial displacement. A cover plate I10 isadvantageously secured to the outer face of the disc I88. Suitable shaftpacking is provided at II2 to prevent leakage of oil from the bearingI58 to the interior of the turbine. In the form illustrated, the packingis of the labyrinth type r and air for sealing purposes may be supplied.to In the space is located an admission chamber "8 for motive fluidhaving an annular outlet "8 for the passage of motive fluid to theturbine. This admission chamber "8 is spaced from the walls of theadjacent parts in much the same manner as is the part 85 described inconnection with Fig. 1, and air or other relatively cool fluid isadmitted to the space I so as to flow in the direction indicated by thearrows in a manner protecting the adjacent turbine parts from heatradiated from the chamber I16. Motive fluid is admitted to chamber II8through suitable inlet openings, none of which appears in thesectionshown in Fig. 4. This protection is particularly desirable forthe packing I82 providing against all leakage from bearing I40 and thepacking for preventing leakage of motive fluid indicated at I84. Thelatter packing is preferably of labyrinth form.

The present embodiment differs from that previously described in thatthe discs for carrying the rows of moving blades of the, turbine areseparate from the turbine shaft. In the present case the turbine shaftI88 is hollow as in the previously described forms, and its outersurface is provided with a series of steps so that the shaft is ofincreasing diameter from theends toward the central part of the shaft.The several turbine discs I88 are provided with shouldered inner boresof diameters such that they .will abut against the proper shoulders ofthe stepped turin assembled position, are fitted so that the flange I80on one disc fits within the recess I82 on an adjacent disc, so that thepins I84 are held against radial displacement. With this arrangement,the turbine rotor can be assembled by sllpping the turbine discs on tothe shaft from the ends thereof, commencing with the discs having thelargest shaft holes, and the discs can be progressively pinned to theshaft as they are assembled. A certain amount of axial clearanceindicated at I88 is left between adjacent turbine discs. This clearanceserves to compensate for expansion and may be made larger than isrequired for expansion. in order to permit hot :motive fluid to reachthe shaft I88. Heating of the shaft to a temperature substantially thesame as that of the discs is desirable in order to minimize differencesin the ratesof expansion and the amount of expansion. In order tofacilitate heating of the shaft, adjacent clearance spaces I96 may beconnected by axially extending slots I98 in the outer surface of theshaft. It will be evident that motive fluid will flow from the clearancespace between two stages of higher pressure to the clearance spacebetween two stages of lower pressure, and in flowing along the shaftwill serve to rapidly and effectively heat the shaft.

In Fig. 6 another'means of heating the shaft is illustrated, inaccordance with which the shaft is drilled at 200 to provide a series ofopenings communicating with'the clearance space between two adjacentdiscs, the adjacent discs preferably being on the portion of the shaftof largest diameter. Gases admitted through the openings 200 to theinterior of the shaft serve to heat it and circulation of gas inside theshaft is provided by means of outlet openings 202 adjacent to the shaftpacking 204, which is, in this form of construction, preferablydifferent in form from the type of packing shown at H2 in Fig.

7 4. Heating of the shaft from the inside is particularly effective inreducing the relative expansion as between the shaft and the turbinecasing. It will be apparent that both the arrangement comprising theannular slots I98 and the arrangement shown in Fig. 6 for admitting gasto the inside of the turbine shaft may be employed in the same turbine.

Referring now more particularly to Figs. 7 and 8, in which the detailsof blade construction are more clearly shown, the outer or. shroud rings206 to which the moving blades 208 are secured,

are provided with two radially extending packing edges 2! and H2, theformer bearing against the inner-surface of easing I32, and the latterbearing against the outer ring 2l4 of an adjacent row of stationaryguide blades. The rings 2|4 are each provided with axially. extendingcircular packing strips H6 and 2!!! to engage the sides of adjacentrings 206. The stationary outer guide rings 2| 4 are Z shaped in crosssection, as in the embodiment illustrated in Fig.1, and carry the rowsof stationary guide blades 220, which at their inner ends are secured tothe inner guide discs 222. In the present embodiment the packing betweenthe guide discs 222 and the turbine rotor comprises radially extendingpacking edges 224 on the turbine .discs, which edges are preferably ofdifferent diameters, and

two axially extending packing strips 226 adapted to engage a suitableradially extending surface on 'an adjacent turbine disc. In this form ofconstruction, as well as in the form shown in Figs. 1 to 3, the outerstationary guide rings 2M may be made in one piece because of the mannerin which the turbine discs are assembled on the shaft by slipping themon from the ends of the shaft. Radially extending pins 228, similar tothe pins 94 shown in Fig. 3, are employed to position rings M4 in thecasing H2, and these pins, as well as pins 94, are advantageously of thesame construction as pins I42 used to unite the casing parts showm inFig. 4. As previously mentioned, numerous different types of mechanicalconnections may be employed for securing the moving and stationaryblades to their resimilar connection 234 is shown, which is weldedbymeans of electric butt welds at 236. Still another form of weldedconnection is indicated at 238 in Fig. 8.

Referring again to Figs. 1 and 4, it will be observed that the meandiameter of each blade row of the motive fluid, it is preferable toconstruct each successive blade row or stage with larger mean diameterthan the preceding row or stage, but this specific construction is notessential to the securing of the benefits of the invention. It isevident that the same general character of path of flow may be obtainedby employing a series of small groups of rows, with the rows within eachgroup having the same diameter, the several groups having diameters ofincreasing value from inlet to outlet. Such constructions are intendedto 'be included within the terms of the appended claims wherein it isstated that the mean diameter of each of the successive stages is ofgenerally increasing value from inlet to outlet. As previously noted,the invention relates to turbines having high thermo-dynamic efli-'ciency which is obtained by multiple stage expansion of the motivefluid. This type of expansion results in a more or less uniformextraction of heat from the motive fluid in passing through the turbine,and consequently the heat drop through the turbine from the inlet end tothe outlet end is gradual and relatively uniform.- The conical path offlow for motive fluid provides a component of flow in radial directionof relatively large value which is particularly advantageous in themultiple stage reaction expansion of a high temperature motive fluid,since the extreme temperature stresses in the inlet portion of the bladesystem, due to the relatively high temperature of the motive fluid inthis portion, are compensated for by the relatively small diameters ofthe blade rows in the inlet portions of the turbine. The blade rowsadjacent the outlet end of the turbine, while of relatively largediameter, are subjected to lower temperature stresses due to the reducedtemperature of the motive fluid when it reaches these rows.Consequently, the combined temperature and mechanical stresses on theparts of the blade system may be made relatively uniform by utilizingwhat may be termed an exaggerated conical form of blade system.

As previously noted, the inlet end of the blade system is kept to assmall a. diameter as is practically possible, and preferably thisdiameter, having regard. to the speed of rotation of the turbine, issuch that the peripheral speed of the blades at the inlet end of theturbine is of the order of 100 meters per second. The very small inletdiameter coupled with the relatively long blades comprises a distinctdeparture from the usual turbine practice, and in the case of a gasturbine for use with high temperature motive fluid produces materiallyimproved results. One of the reasons for such improvement is the factthat, due to the high temperature of the motive fluid, substantialclearances must be used to allow for the relatively great expansion, andwith the long blades operating on a small diameter, the

55 manner relieving the structure from serious area of the clearancespaces relative to the area of the path of flow for motive fluid is verysmall even with the relatively great absolute leakage to allow for thecreep" in the metal,

which will occur when motive fluid of as high temperature as thatcontemplated in the present case is expanded in the manner necessary tosecure high thermo-dvnamic efliciency.

The use of small diameter blade rows at the inlet end of the turbineappears to be directly at variance with the teachings of the prior artwhich lead to the utilization of blade rows of maximum practicaldiameter throughout the length of theturbine in order to secure a highvalue for the sum of the squares of the blade speeds. The latter factoris one of the factors determinative of the Parsons figure of theturbine, and-should be high to insure a turbine having highthermodynamic efflciency. Due, however, to the fact that the gaseousmotive fluid has a relatively low specific heat value, it is possible toemploy the construction according to the present invention and to securethe many advantages of such construction without having to resort to anundue number of stages of blading in the blade system in order to obtain9. Parsons flgure for the turbine having a value high enough to insurehigh thermo-dynamic efllciency.

It will further be observed from the figures that the form ofconstructionin accordance with the present invention permits arelatively great amount of expansion, which is necessaryin the turbine,and the creep of the metal to take place without causing destructivestresses to be set up in the turbine structure. The turbine shaft, whichis subjected at the inlet end of the turbine to the relatively closeproximity oi high temperature gases is quickly and readily heated-moreor less uniformly with the blade system, and the form and constructionof the turbine casing permits this part to be also readily and quicklyheated without setting up dangerous stresses therein. Furthermore, themanner in which the stationary guide blades are assembled in the casingpermits freedom of radial expansion in a stresses. Free relative axialexpansion between the shaft and the turbine casing is provided for, dueto the form and arrangement of the shaft bearings, and it will be notedthat the shaft is anchored axially with respect to the casing at a placeadJacent to the exhaust or outlet end of the turbine. This is important,since the radial clearance spaces at the outlet end of the turbine mustbe greater than the corresponding clearance spaces at the inlet end ofthe turbine where the blade rows are of relatively small diameter.Consequently, it is highly desirable to maintain the axial packing forthe blade rows at the outlet end of the turbine as tight as possible,and this desired result is materially aided by anchoring the turbineshaft axially with respect to the casing close to the outlet end of theturbine blading. At the inlet end of the turbine, where the maximumrelative movement axially between the shaft and the casing takes place,the radial packings involve very considerably smaller clearance spaces,and consequently are more effective than the radial packings with largeclearances at the outlet end of the turbine.

As previously noted, the blade systems in Figs. 1 and 4 differ in thatin the system shown in Fig. 4 the lengths of the blades relative to themean diameters of the blade rows decrease from the inlet end of theturbine toward the outlet end of the turbine, whereas in the structureshown in Fig. 1, the relative lengths remain substantially constant. Theamount of the decrease in the relatLve lengths of the blades will, ofcourse, vary depending upon how much residual energy it is desired tohave in the exhaust gases in the form of outlet velocity, but by way ofexample, it may be stated that in a turbine of the character shown inFig. 1, having blades at the inlet end the length of which is of themean diameter of the blade row at the inlet end, the length of theblades at the outlet end of the turbine may advantageously be in theneighborhood of 15% to 16% of the mean diameter of the outlet blade row.

From the foregoing description it will be evident that many changes andmodifications may be made without departing from the spirit of theinvention, and further, that certain features of the invention may beemployed to the exclusion of others. It is accordingly to be understoodthat the invention embraces all forms of apparatus that may fall withinthe terms of the appended claims when construed as broadly as isconsistent with the state of the prior art.

What I claim is:

1. A gas turbine for extracting energy from gaseous motive fluid at anadmission temperature of at least 800 C. absolute comprising a rotor, acircumferentially integral casing of generally conical form increasingin diameter from the inlet to the outlet end of the turbine in a seriesof cylindrical steps, there being one step for each stage of theturbine, said rotor comprising a plurality of rows of moving turbineblades, and a plurality of rows of stationary guide blades between saidrows of moving blades, said rows of stationary guide blades comprisingstepped outer blade rings having outer surfaces cooperating with thestepped surfaces of the casing, said blade rings being insertable andremovable axially of and independently expansible in radial directionwith respect to said casing and radially extending pins for securing thesaid rings in said casing.

2. A gas turbine for extracting energy from gaseous motive fluid at anadmission temperature of at least 800 C. absolute comprising a rotor anda casing, said rotor comprising a shaft and a plurality of turbine discscarried by the shaft, said turbine discs having flanged and recessedportions at their inner circumferences, radially extending pins passingthrough said flanged portions for securing the discs to the shaft, thediscs radially expansible with respect to said shaft and said pins beingpositioned with the flange of one disc located in the recess of anadjacent disc whereby to prevent radial displacement of said pins, and aplurality of rows of stationary guide blades carried by said turbinecasing and extending radially inwardly between adjacent turbine discs.

3. In an axial flow gas turbine of the character described, a rotorcomprising a shaft, an integral casing around the rotor, said casingbeing open at the exhaust end of the turbine, an end member for theoutlet end of the turbine comprising a ring part secured to the casing.,a plurality of ribs extending radially inwardly from said ring part andan inner part connected to the inner ends of said ribs, said inner partsupporting a bearing for said shaft and said ribs being adjacent to thelast row of turbine blades, whereby to provide a direct exhaust in axialdirection from said last row of blades through the spaces between theribs, and a tapered hollow shield extending axially of the turbine fromthe inner ends of said ribs for guiding flow of said direct axialexhaust, whereby to reduce the outlet loss of the turbine.

4. In an axial flow gas turbine of the character described, acircumferentially integral conical casing having an inner surface in theform of a plurality of steps, turbine blading comprising a plurality ofguide blade rings the outer surfaces of which are stepped or shoulderedto fit the steps in the casing surface and mounted for free radialexpansion with respect to the casing, a plurality of rows of movingblades having outer shroud rings, and axial packing between said outershroud rings and the adjacent guide blade rings.

5. In an axial flow gas turbine of the character described, acircumferentially integral conical casing having an inner surface in theform of a plurality of steps, turbine blading comprising a plurality ofguide blade rings the outer surfaces of which are stepped or shoulderedto fit the steps in the casing surface and mounted for free radialexpansion with respect to the casing, a plurality of rows of movingblades having outer shroud rings, axial packing between said outershroud rings and the adjacent guide blade rings, and radial packingbetween said outer shroud rings and both the casing and an adjacentguide blade ring.

6. In an axial flow gas turbine of the character described, a rotorhaving a shaft, casing structure including a conical portion around therotor and an end member at the outlet end of the turbine comprising aplurality of ribs extending radially inwardly from said conical portionand an inner part connected to the inner ends of said ribs, a bearingcarried by said inner part for supporting one end of said shaft and forholding said one end of the shaft in fixed axial relation with respectto said end member, a separate supporting member attached to said casingstructure adjacent to the inlet end of the turbine, said supportingmember being fixed axially and mov- H able radially with respect to thecasing structure, and a bearing carried by said supporting memher forsupporting said shaft at the inlet end of the turbine, said shaft beingmovable axially with respect to said last mentioned bearing.

7. In an axial flow gas turbine 01' the character described, a rotorhaving a shaft, a circumferentially integral casing surrounding saidrotor, a plurality of rows of moving blades each having an annular innerblade ring, each of said inner blade rings being axially spaced fromadjacent rings to provide for individual axial expansion of the rings onthe shaft and each of said rings being secured to the shaft by radiallyextending pins whereby to permit radial expansion of the rings withrespect to the shaft, a plurality of rows of fixed guide blades locatedbetween said rows of moving blades and each having an outer blade ring,and a plurality of radially extending pins for independent mounting ofeach of said outer blade rings in said casing, there being clearancebetween said outer blade rings and said age -12a casing to permit radialexpansion of the rings with respect to the casing.

8. An axial flow turbine of the character described, including a rotorhaving moving blading and a'bearing at the inlet end of the turbine,supporting structure including a part carrying said bearing, acircumferentiallyintegral conical casing part around said moving bladingand carrying stationary blading cooperating with said moving blading toform a blade system, and means for connecting said casing part to saidsupporting structure so as to permit free radial expansion of saidcasing part with respect to said supporting structure at the place ofattachment thereto and to said rotor adjacent to the inlet end of theturbine.

9. An axial flow turbine of the character described, including a rotorhaving moving blading and a bearing at the inlet end of the turbine,supporting structure including a part carrying said bearing, acircumferentially integral conical casing part around said movingblading and carrying stationary blading cooperating with said movingblading to form a blade system, and a plurality of radially extendingpins connecting said casing part to said supporting structure so as topermit free radial expansion of said casing part with respect to saidsupporting structure at the place of attachment thereto and to saidrotor adjacent to the inlet end of the turbine.

10. An axial flow turbine of the character described, including a rotorhaving a plurality of rows of moving blades thereon and a bearing at theinlet end of the turbine, supporting structure for supporting saidbearing, a circumferentially integral conical casing around said rows ofmoving blades and carrying rows of stationary blades cooperating withsaid rows of moving blades to form a blade system, means for connectingsaid casing to said supporting structure for free radial expansionthereof with respect to said structure at the place of attachmentthereto, and a plurality of rows of stationary guide blades carried bysaid casing and freely expansible with respect thereto in radialdirection.

11. An axial flow turbine 01 the character described, including a rotorhaving a plurality of rows of blades, supporting structure forsupporting said rotor at the inlet end of the turbine, a conical casingaround said blade rows, means for connecting said casing to saidsupporting structure for free radial expansion of the casing withrespect to said structure at the inlet end of the turbine, a pluralityof rings of stationary guide blades carried by 'said casing and freelyexpansible with respect thereto in radial direction, and an admissionchamber for motive fluid housed within said supporting structure, saidadmission chamber being spaced from said supporting structure and beingfreely expansible with respect thereto.

12. Anlaxial flow turbine of the character described, including a rotorhaving a plurality of rows of blades, supporting structure forsupporting said rotor at the inlet end of the turbine, a conical casingaround said blade rows, means for connecting said casing to saidsupporting structure for free radial expansion of the casing withrespect to said structure at the inlet end of the turbine, a pluralityof rings of stationary guide blades carried by said casing and freelyexpansible with respect thereto in radial direction, an admissionchamber for motive fluid housed within said supporting structure, saidadmission chamber being spaced from said supporting structure a d beingfreely expansible with respect theret and said chamber having an outletfor full admission of motive fluid to the first row oi moving blades,and a ring of fixed guide vanes for guiding the motive fluid deliveredfrom said chamber.

13. In an axial flow turbine, a. rotor including a plurality of rows ofmoving blades having shroud rings oi. progressively increasing diameterfrom the inlet to the outlet end of the turbine, a stepped casingmember, a plurality of rows 01' stationary guide blades carried by saidcasing member and freely expansible with respect thereto in radialdirection, each row of guide'blades including a stepped outer ring parthaving a portion located radially outwardly or and axially overlappingan adjacent shroud ring.

14. In an axial flow turbine, a,'rotor including a plurality of rows ofmoving blades having shroud rings, a casing around said rotor, aplurality of rows of stationary guide blades alternating with the rowsof moving blades, and radially extending pins for supporting said rowsof guide blades in freely expansible relation in radial direction withrespect to said casing, the rows of guide blades including partsextending radially outwardly of and overlapping adjacent shroud rings.

15. A high temperature gas turbine for extracting energy from gaseousmotive fluid comprising products of combustion at an admissiontemperature 01' at least 800 C. absolute, including a multiple stageaxial flow blade system, the mean diameter of each of the successivestages being of generally increasing value from the inlet stage to theoutlet stage oi. said system, the ratio of the length of the blades inthe inlet row of moving blades to the mean diameter of said inlet rowbeing at least as great as the ratio of the length oi! the blades in theoutlet row of moving blades to the mean diameter of said outlet row, andmeans providing for full admission oi motive fluid to the inlet stage ofsaid blade system.

16. A high temperature gas turbine for extracting energy from gaseousmotive fluid comprising products of combustion at an admissiontemperature of at least 800 C. absolute, including a multiple stageaxial flow blade system, the mean diameter of each of thesuccessivestages being of generally increasing value from the inlet stage to theoutlet stage of said system, the ratios 01' the lengths of the blades tothe mean diameters of their respective rows being substantially constantfrom the inlet end'to the outlet end of said blade system, and meansproviding for full admission of motive fluid to said blade system.

17. A high temperature gas. turbine for extracting energy from gaseousmotive fluid comprising products of combustion at an admissiontemperature of at least 800 C. absolute, including a multiple stageaxial flow blade system, the mean diameter of each of the successivestages being of generally increasing value from the inlet stage to theoutlet stage oi! said system, the ratios of the lengths of the blades tothe mean diameters of their respective rows progressively decreasingfrom the inlet stage to the outlet stage of said blade system, and meansproviding for full admission of motive fluid to the inlet stage of saidblade system.

18. A high temperature gas turbine for extracting energy from gaseousmotive fluid comprising products 01 combustion at an admissiontemperature of at least 800C. absolute including a multiple stage axialflow blade system, the mean diameter of each of the successive stagesbeing of generally increasing value from the inlet stage to the outletstage of said system, the inlet stage 01' said system including a row ofmoving blades having a length within a range the lower limit of which isat least one-tenth and the upper limit of which is of the order ofone-fifth of the mean diameter oi said row and the ratio of the length01 the blades oi! said row to the mean diameter oi said row being atleast as great as the ratio of the length of the moving blades in theoutlet stage of said system to the mean diameter of the moving blade rowof said outlet stage, and means providing for full admission of motivefluid to the inlet stage of said blade system.

19. A high temperature gas turbine for extracting energy from gaseousmotive fluid comprising products of combustion at an admissiontemperature of at least 800 C. absolute. including a multiple stageaxial flow blade system, the mean diameter of each of the successivestages being of generally increasing value from the inlet stage to theoutlet stage of said system, the inlet stage of said system comprising arow of moving blades having a length within a range the lower limit ofwhich is at least one-tenth and the upper limit of which is of the orderof one-fifth of the mean diameter of said row, the ratios of the lengthsof the blades in moving rows of the remaining stages of said system tothe mean diameters of their respective blade rows being substantiallythe same as the ratio of the length of the blades in the first mentionedrow to the mean diameter thereof, and means providing for full admissionof motive fluid to the inlet stage of said blade system. I

20. A high temperature gas turbine for extracting energy from gaseousmotive fluid comprising products of combustion at an admissiontemperature of at least 800 C. absolute, including a multiple stageaxial flow blade system, the mean diameter of each of the successivestages being oi generally increasing value from the inlet stage to theoutlet stage of said system, the inlet stage of said system including arow of moving blades having a length within a range the lower limit ofwhich is at least one-tenth and the upper limit of which is oi. theorder of one-fifth oi the mean diameter of said blade row, the ratios ofthe lengths of the blades of the moving rows of the remaining stages ofthe system to the mean diameters 01 their respective rows progressivelydecreasing from the maximum value established in said inlet stage of thesystem to a minimum value in the outlet stage of said system, and meansproviding, for full admission of motive fluid to the inlet stage of saidblade system. a

21. A high temperature gas turbine for ex tracting energy from gaseousmotive fluid comprising products'of combustion at an admissiontemperature of at least 800 C. absolute, including a multiple stageaxial flow blade system, the mean diameter of each of the successivestages being of generally increasing value from the inlet stage to theoutlet stage of said system, the inlet stage of said system comprising arow of moving blades having a length within a range the lower limit oiwhich is at least one-tenth and the upper limit of which is of the orderof one-fifth oi the mean diameter of said blade row, the ratios of thelengths of the blades of the remaining rows of the system to the meandiameters of their respective rows progressively decreasing from themaximum value established in said inlet stage of the system to a minimumvalue in the outlet stage 01' said system, said minimum value being ofthe order 01' three-quarters of said maximum value, and means providingfor full admission of motive fluid to the inlet stage of said bladesystem.

22. A high temperature gas turbine for extracting energy from gaseousmotive fluid comprising products of combustion at an admissiontemperature of at least 800 C. absolute, including a multiple stageaxial flow blade system, the mean diameter of each of the successivestages being of generally increasing value from the inlet stage to theoutlet stage of said system, the diameter of the inlet stage being sosmall that at the normal speed of operation of the turbine the speed ofthe moving blades of said inlet stage is of the order of 100 meters persecond, the length of the moving blades of said inlet stage being withina range the lower limit of which is at least one-tenth and the upperlimit of which is of the order of one-fifth of the mean diameter of therow of which they form a part and the ratios of the length of the bladesof said row to the mean diameter of said row being at least as great asthe ratio of the length of the moving blades in the outlet stage of saidsystem to the mean diameter of the moving blade row of said outletstage, and means providing for full admission of motive fluid to theinlet stage of said blade system.

23. In an axial flow gas turbine of the character described, a rotorhaving a shaft, a circumferentially integral casing around the rotor,said rotor and said casing carrying blades cooperating to form a bladesystem providing a path of flow in which the ratios of the lengths ofthe blades to the mean diameters of the blade rows of which they form apart are of decreasing value from the inlet toward the outlet ofthesystem, whereby to provide an expansion path for the gases resultingin high residual exhaust velocity thereof, an end member for the outletend of the turbine comprising a ring part secured to the casing, aplurality of ribs extending radially inwardly from said ring part and aninner part connected to the inner ends of said ribs, said inner partsupporting a bearing for said shaft, and said ribs being adjacent to thelast row of turbine blades whereby they provide a direct exhaust inaxial direction from said last row of blades through the spaces betweensaid ribs.

24. In an axial flow gas turbine of the character described, a rotorhaving a shaft, a circumferentially integral casing around the rotor,said rotor and said casing carrying blades cooperating to form a bladesystem providing a path of flow in which the ratios of the lengths ofthe blades to the mean diameters of the blade rows of which they form apart are of decreasing value from the inlet toward the outlet of thesystem, whereby to provide an expansion path for the gases resulting inhigh residual exhaust velocity thereof, an end member for the outlet endof the turbine secured to said casing and including an inner partsupporting a bearing for said shaft and a plurality oi radiallyextending ribs adjacent to the last, row of turbine blades, said ribsproviding axially extending guide surfaces for guiding the exhaust gasesin direct axial flow from the turbine.

25. A high temperature gas turbine for extracting energy from gaseousmotive fluid comprising products of combustion at an admissiontemperature of at least 800 C. absolute, including a multiple stageaxial flow blade system, the mean diameter of each oi the successivestages being of generally increasing value from the inlet stage to theoutlet stage of said system and said system having blades the lengths ofwhich are of generally increasing value from the inlet stage to theoutlet stage of said system, the ratio of the length of the blades inthe inlet row of moving blades to the mean diameter of said inlet rowbeing at least as great as the ratio of the length of the blades in theoutlet row of moving blades to the mean diameter of said outlet row, andmeans providing for full admission of motive fluid to the inlet stage ofsaid blade system.

26. A high temperature gas turbine for extracting energy from gaseousmotive fluid comprising products of combustion at an admissiontemperature of at least 800 C. absolute, including a multiple stageaxial flow blade system, the mean diameter of each of the successivestages being of generally increasing value from the inlet stage to theoutlet stage of said system, and said system having blades the lengthsof which are of generally increasing value from the inlet stage to theoutlet stage, the ratios of the length of the blades to the diameters oftheir respective rows being substantially constant from the inlet end tothe outlet end of said blade system, and means providing for fulladmission of motive fluid to said blade system.

27. A high temperature gas turbine for extracting energy from gaseousmotive fluid comprising products of.c0mbustion at an admissiontemperature of at least 800 C. absolute, including a multiple stageaxial flow blade system, the mean diameter of each of the successivestages being of generally increasing value from the inlet stage to theoutlet stage of said system, and said system having blades the lengthsof which are of generally increasing value from the inlet stage to theoutlet stage, the ratios of the lengths of the blades to the meandiameters of their respective rows progressively decreasing from theinlet stage to the outlet stage of said blade system, and meansproviding for full admission of motive fluid to the inlet stage of saidblade system.

ALF LYSHOLM.

CERTIFICATE OF CORRECTION.

Patent No. 2,080,425. May is, 1937.

' ALF LYSHOLM.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,first column, line 1 before the words "Briefly stated" insert thefollowinglparagraphs:

The present invention relates to turbines, and has particular referenceto turbines intended to be operated with a motive fluid of hightemperature. Still more particularly, the invention relates togas-turbines adapted to be employed in gas turbine systems of thecontinuous combustion type and adapted to utilize motive fluid having arelatively low admission pressure, for example, from four to tenatmospheres, and having an admission temperature of at least 800Cabsolute. p

In some of its aspects the invention relates particularly to gasturbines of the axial flow type adapted to be embodied in a unit in agas turbine system, in which the turbine is directly associated with adevice to be driven thereby, such for example as a compressor providinga compressed gaseous medium to be utilized as a constituent of themotive fluid for the turbine. Further aspects of the invention relate toturbines of the above character which are adapted to provide propellingeffect due to the reactive or rocket effect of exhaust gases dischargedfrom the turbine at high velocity.

and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Office.

Signed and sealed this 27th day of July. A. D. 1957.

Henry Van Arsdale (Seal) Acting Commissioner of Patents.

